Antenna device of mobile terminal

ABSTRACT

An antenna device of a mobile terminal that can secure radiation performance is provided. The antenna device having a battery cover composed of a metal material includes a radiation unit for transmitting and receiving a signal, a feeding unit formed at an end portion of a first side of the radiation unit for electrically connecting the radiation unit to a Printed Circuit Board (PCB), and a ground part disposed a predetermined distance from the feeding unit and formed at a second side of the radiation unit. When the battery cover is fastened to the mobile terminal, the ground part contacts a first side of the battery cover.

PRIORITY

This application is a continuation of application Ser. No. 12/489,044,filed Jun. 22, 2009, which claims priority under 35 U.S.C. §119(a) toKorean Patent Application No. 10-2008-0058619 filed in the KoreanIntellectual Property Office on Jun. 20, 2008, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an antenna device, and moreparticularly, to an antenna device of a mobile terminal that can changea monopole type antenna to a Planar Inverted-F Antenna (PIFA) bygrounding one side of the monopole type antenna to a battery covercomposed of a metal material in order to secure radiation performance ofthe mobile terminal when the battery cover composed of a metal materialis fixed to the mobile terminal.

2. Description of the Related Art

In accordance with user demand, mobile terminals have decreased size andthickness and provide various functions according to a digitalconvergence trend. For example, mobile terminals provide a service usinga communication function such as digital broadcasting reception, GlobalPositioning System (GPS), Bluetooth, Radio Frequency Identification(RFID), and mobile commerce. The mobile terminal providing thecommunication function has one or more antennas. The antenna efficientlytransmits or receives a signal in order to perform wirelesscommunication.

Since mobile terminals have decreased in size and thickness, housings ofthe mobile terminals have reduced in strength. In order to solve thestrength problem of the mobile terminal housing, the mobile terminalhousing is composed of a metal material. However, the mobile terminalhousing composed of a metal material adversely affects radiationperformance of the antenna. Particularly, when a battery cover composedof a metal material is positioned adjacent to the antenna, a parasiticresonance occurs, whereby radiation performance of the antennadeteriorates. Therefore, when using a mobile terminal housing composedof a metal material, an antenna device in which radiation performance ofthe mobile terminal does not deteriorate is desirable.

SUMMARY OF THE INVENTION

The present invention has been made to address at least the aboveproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the present inventionprovides an antenna device that can secure radiation performance in amobile terminal having a battery cover composed of a metal material byconnecting the battery cover and a side of an antenna.

According to an aspect of the present invention, an antenna device of amobile terminal having a battery cover composed of a metal materialincludes a radiation unit for transmitting and receiving a signal, afeeding unit formed at an end portion of a first side of the radiationunit for electrically connecting the radiation unit to a printed circuitboard (PCB), and a ground part disposed a predetermined distance fromthe feeding unit and formed at a second side of the radiation unit. Whenthe battery cover is fastened to the mobile terminal, the ground partcontacts a first side of the battery cover.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentinvention will be more apparent from the following detailed descriptionwhen taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagram illustrating a perspective view of a rear surface ofa mobile terminal, according to an embodiment of the present invention;

FIG. 2A is a diagram illustrating a partially cut away perspective viewof the rear surface of the mobile terminal of FIG. 1;

FIG. 2B is a diagram illustrating a perspective view of a fastened stateof an antenna device and a battery cover in the rear surface of themobile terminal of FIG. 1;

FIG. 3A is a diagram illustrating a perspective view of the antennadevice of the mobile terminal of FIG. 2B;

FIG. 3B is a diagram illustrating a perspective view of the batterycover of the mobile terminal of FIG. 2B;

FIG. 4A is a diagram illustrating radiation performance of the antennadevice of FIG. 3A when the battery cover is not fastened to the mobileterminal;

FIG. 4B is a diagram illustrating radiation performance of aconventional antenna device in which a battery cover is fastened to amobile terminal not in contact with an antenna device; and

FIG. 4C is a diagram illustrating radiation performance of the antennadevice of FIG. 3A when the battery cover is fastened to the mobileterminal in contact with the antenna device.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

Embodiments of the present invention are described in detail withreference to the accompanying drawings. The same or similar componentsare designated by the same or similar reference numerals although theyare illustrated in different drawings. The views in the drawings areschematic views only, and are not intended to be to scale or correctlyproportioned.

Detailed descriptions of constructions or processes known in the art maybe omitted to avoid obscuring the subject matter of the presentinvention.

In the following description, a mobile terminal according to the presentinvention includes a battery cover composed of a metal material and anantenna, and may be an information and communication device or amultimedia device such as a mobile communication terminal, mobile phone,Personal Digital Assistant (PDA), smart phone, International MobileTelecommunication 2000 (IMT-2000) terminal, Code Division MultipleAccess (CDMA) terminal, Global System for Mobile Communication (GSM)terminal, Universal Mobile Telecommunication Service (UMTS) terminal,digital broadcasting terminal, and applications thereof.

Hereinafter, “radiation performance” is a transmission and receptionability of an antenna device, i.e. an ability to enable the antennadevice to receive a signal transmitted by other terminals with minimumdamage to the signal and to transmit a signal to other terminals withminimum damage to the signal.

A “monopole antenna” is an antenna having one grounded side, unlike adipole antenna, which uses both poles. Because a grounded portiongenerates an image effect, the monopole antenna has the same effect asthat of a dipole antenna. In a mobile terminal, because the monopoleantenna uses the ground of the mobile terminal, the monopole antenna hasa reduced length compared to the dipole antenna.

A “planar inverted-F antenna (PIFA)” is an antenna having an invertedF-shape including a PCB, radiator, feeding unit, and ground unit.

FIG. 1 is a diagram illustrating a perspective view of a rear surface ofa mobile terminal, according to an embodiment of the present invention.

Referring to FIG. 1, a mobile terminal according to the presentembodiment includes an upper body 70 having a display unit and a lowerbody 50 for inserting a battery. The mobile terminal is a bar typemobile terminal in which an antenna device 100 is mounted in the lowerbody 50. However the mobile terminal of the present invention is notlimited thereto and may be a mobile terminal of various other types,such as a folder type and a slide type.

The lower body 50 has a space for inserting a battery, and a batterycover 40 is fastened to the mobile terminal to prevent the battery frombeing separated from the mobile terminal. The lower body 50 has grooves51, 54, and 55 at an upper end of an opened region in order to securelyfasten the battery cover 40.

The battery cover 40 has a rectangular shape and has a protrusion part41 and first auxiliary protrusion parts 44 and 45 corresponding to thegrooves 51, 54, and 55, respectively, of the lower body 50 at a firstside thereof. When the battery cover 40 is fastened to the lower body50, the antenna device 100 contacts the protrusion part 41.

FIG. 2A is a diagram illustrating a partially cut away perspective viewof the rear surface of the mobile terminal of FIG. 1. FIG. 2B is aperspective view illustrating a fastened state of the antenna device 100and the battery cover 40 in the rear surface of the mobile terminal ofFIG. 1.

Referring to FIGS. 1 to 2B, the mobile terminal includes the batterycover 40, the lower body 50, a PCB 60, the upper body 70, and theantenna device 100.

The PCB 60 is a thin plate for mounting electronic parts and elementsfor use in the mobile terminal, such as an Integrated Circuit (IC),resistor, capacitor, and switch, and includes wiring circuits forelectrically connecting the mounted electronic parts and elements.Particularly, the PCB 60, according to the present embodiment, ismounted in the upper body 70 and includes an antenna contact part 61formed at a side portion of a surface facing towards the battery cover40.

The antenna contact part 61 is an electrical contact for supplying anelectric signal to the antenna device 100 and has a rectangular shape.However a shape of the antenna contact part 61 is not limited theretoand the antenna contact part 61 can have various shapes, such as acircle and a rhombus.

The antenna device 100 is mounted at an inner part of the lower body 50,and is positioned between the PCB 60 and the lower body 50. The antennadevice 100 is electrically connected to the antenna contact part 61.Further, when the battery cover 40 is fastened to the lower body 50, theantenna device 100 contacts the battery cover 40. For this, the antennadevice 100 includes a feeding unit 20 connected to the antenna contactpart 61, a ground part 30 connected to the battery cover 40, and aradiation unit 10 for transmitting and receiving a signal. Further, theantenna device 100 has a groove for fixing the antenna device 100 to thelower body 50. The antenna device 100 is described in detail below.

The lower body 50 is an external housing of the mobile terminal, and abattery is mounted in the lower body 50. Particularly, the lower body50, according to the present embodiment, mounts the antenna device 100at an inner part thereof. It is preferable that the lower body 50 ismade of a nonmetal material in order for the antenna device 100 toenable efficient radiation of a signal.

The upper body 70 is an external housing of the mobile terminal in whichthe PCB 60 including electronic parts is mounted, and is coupled to thelower body 50. The upper body 70 has fastening parts 71 and 72 forinserting and fixing second auxiliary protrusion parts 43 and 46 (shownin FIG. 3B) of the battery cover 40. Particularly, at least part of theupper body 70, according to the present embodiment, is composed of ametal material, for example, Steel Use Stainless (SUS). Further, theupper body 70 is connected at one side to the ground of the PCB 60. Asupport 74 is formed at one side of the upper body 70, for example, at asurface opposite to the PCB 60, as shown in FIG. 2A, so that the PCB 60securely contacts the ground.

The battery cover 40 has a rectangular shape and has the protrusion part41 for contacting with the ground part 30 of the antenna device 100, andthe first auxiliary protrusion parts 44 and 45 and second auxiliaryprotrusion parts 43 and 46 for preventing the battery cover 40 frombeing separated from the mobile terminal. Particularly, the batterycover 40, according to the present embodiment, is composed of a metalmaterial, for example, SUS. When the battery cover 40 is fastened to thelower body 50, the protrusion part 41 is fastened to the ground part 30.Specifically, referring to the enlarged portion of FIG. 2B, the groundpart 30 has a first extension part 32 extending from a side of theradiation unit 10 and perpendicular thereto, and has a first projection31 formed at a lower surface of an end portion of the first extensionpart 32. The protrusion part 41 has a second extension part 47 formed ata lower surface of the battery cover 40 at a predetermined distance froman outer edge thereof. A third extension part 48 is formed at an outerend of the second extension part 47 and extends parallel to the batterycover 40 in a direction away from the outer edge of the battery cover 40to project at a predetermined distance therefrom. A second projection 42is formed at an upper surface of an end portion of the third extensionpart 48.

When the protrusion part 41 and the ground part 30 are fastened, thefirst extension part 32 and the third extension part 48 are disposedparallel, the first projection 31 is positioned between the secondprojection 42 and the second extension part 47, and the secondprojection 42 is positioned between the first projection 31 and theradiation unit 10. When the battery cover 40 is attached to the lowerbody 50, the first projection 31 and the second projection 42 aredisposed in a line in the direction of movement at attachment, and canonly be separated by a force greater than a predetermined force. It ispreferable that the first projection 31 and the second projection 42 areformed having a circular cross-sectional form (for example, ahalf-circle).

However, a form of the first projection 31 and the second projection 42are not limited thereto. Accordingly, the ground part 30 and theprotrusion part 41 can be fastened in various forms according to adesigner's intention.

When the battery cover 40 is fastened to the lower body 50, the feedingunit 20 is electrically connected to the antenna contact part 61included in the PCB 60, the ground part 30 contacts the protrusion part41 of the battery cover 40, and thereby the antenna device 100 operatesas a PIFA. The battery cover 40 performs a function as the ground of theantenna device 100 as an element of the antenna device 100, instead ofacting as a separate element that adversely affects radiationperformance of the antenna device 100. Further, the battery cover 40contacts the upper body 70 to extend the ground of the antenna device100. Specifically, when the battery cover 40 is fastened to the lowerbody 50, the battery cover 40 contacts a side surface of the upper body70, specifically at regions 70 a and 40 a (as shown shaded in FIG. 2A).It is preferable that the upper body 70 is composed of a metal material.Further, as described above, as the upper body 70 contacts the ground ofthe PCB 60, the battery cover 40, the upper body 70, and the ground ofthe PCB 60 are connected to form one ground.

When the battery cover 40 is not fastened to the lower body 50, theantenna device 100 operates as a monopole antenna in which only thefeeding unit 20 is electrically connected to the antenna contact part61.

In FIGS. 1 to 2B, the antenna device 100 is positioned at an upper endof the mobile terminal and the battery cover 40 is fastened to a lowerend thereof, however the present invention is not limited thereto. Forexample, the present invention may have a structure in which the antennadevice 100 is positioned at a lower end of the mobile terminal and thebattery cover 40 is fastened to an upper end thereof.

FIG. 3A is a diagram illustrating a perspective view of the antennadevice 100 in more detail.

Referring to FIGS. 1 to 3A, the antenna device 100 includes theradiation unit 10, and the feeding unit 20 formed at an end portion ofone side of the radiation unit 10 to electrically connect the PCB 60 andthe radiation unit 10. The antenna device 100 also includes the groundpart 30 disposed a predetermined distance from the feeding unit 20 andformed at one side of the radiation unit 10.

The radiation unit 10 is a metal plate (for example, a copper or nickelsilver plate) having a predetermined width and thickness and having apredetermined shape such as a “

”-shape. At one side of the radiation unit 10, the feeding unit 20, forconnecting the PCB 60 and the radiation unit 10, and the ground part 30,for connecting the battery cover 40 and the radiation unit 10, areformed. The radiation unit 10 has a predetermined length according to awavelength λ of a using frequency f. The radiation unit 10 generally hasa length λ/4.

The radiation unit 10 has one or more grooves 11 for preventing theantenna device 100 from moving. The groove 11 may be formed as a hole. Ashape of the radiation unit 10 is not limited to the “

“-shape. That is, the radiation unit 10 can take various forms such as alinear shape, “

“-shape, and a zigzag shape according to a design of a mobile terminal,a designer's intention, and radiation performance.

The feeding unit 20 is positioned at an end portion of one side of theradiation unit 10 so as to connect the PCB 60 and the radiation unit 10,thereby functioning as a passage for supplying an electrical signal tothe radiation unit 10. The feeding unit 20 includes a connection memberfor electrically connecting the radiation unit 10 to the PCB 60. Forexample, the connection member may be a clip 21 having a “C”-shape(hereinafter, C-clip). The C-clip 21 is integrally formed with thefeeding unit 20 and preferably has elasticity so as to sustain a contactwith the PCB 60. However, the C-clip 21 of the present invention is notlimited thereto. For example, the C-clip 21 may be mounted in theantenna contact part 61 of the PCB 60.

The ground part 30 is disposed a predetermined distance from the feedingunit 20 and formed at one side of the radiation unit 10. When thebattery cover 40 is fastened to the lower body 50, the ground part 30contacts the protrusion part 41 of the battery cover 40. The ground part30 sustains a contact with the battery cover 40 through the firstprojection 31 for preventing separation from the battery cover 40. Aform of the first projection 31 is not limited to that shown in FIG. 3A,and may take various forms according to a fastened structure. Forexample, the first projection 31 may take a nipper form that grips thebattery cover 40.

The antenna device 100 has a varying resonance frequency according to adistance between the feeding unit 20 and the ground part 30, and thelength and width of the ground part 30. An optimized value of thedistance between the feeding unit 20 and the ground part 30 and of thelength and width of the ground part 30 can be obtained throughexperimentation.

The antenna device 100 operates as a monopole antenna or a PIFAaccording to fastening of the battery cover 40. Specifically, when thebattery cover 40 is not fastened to the lower body 50, only the PCB 60and the feeding unit 20 are electrically connected, and the antennadevice 100 operates as a monopole antenna. When the battery cover 40 isfastened to the lower body 50, the PCB 60 and the feeding unit 20 areelectrically connected, the ground part 30 and the battery cover 40 areconnected, and the antenna device 100 operates as a PIFA. Further, theantenna device 100 is mounted in a carrier to be mounted to the mobileterminal.

In the present embodiment, the radiation unit 10 of the antenna device100 is formed as a monopole antenna. However a form of the radiationunit 10 is not limited thereto, and the radiation unit 10 may be formedas a PIFA. In this case, the battery cover 40 extends the ground of thePIFA.

FIG. 3B is a diagram illustrating a perspective view of the batterycover 40 in more detail.

Referring to FIGS. 1 to 3B, the battery cover 40 has a rectangularshape, and the battery cover 40 has the protrusion part 41 forcontacting with the ground part 30 when the battery cover 40 is fastenedto the lower body 50. The protrusion part 41 has the second projection42 to be fastened to the ground part 30. Further, the battery cover 40has the first auxiliary protrusion parts 44 and 45 and second auxiliaryprotrusion parts 43 and 46 for preventing separation from the lower body50. It is preferable that the first auxiliary protrusion parts 44 and 45adjacent to the antenna device 100 are made of a nonmetal material inorder to secure radiation performance of the antenna device 100.

Particularly, the battery cover 40, according to the present embodiment,is composed of a metal material, for example, SUS. When the protrusionpart 41 formed as the battery cover 40 contacts the ground part 30, thebattery cover 40 performs a function as the ground of the antenna device100. Accordingly, the antenna device 100 operates as a PIFA. When thebattery cover 40 is fastened to the lower body 50 of the mobileterminal, the antenna device 100 is changed from a monopole antenna to aPIFA.

When the upper body 70 is composed of a metal material, as the batterycover 40 contacts one side of the upper body 70, and one side of theupper body 70 contacts the ground of the PCB 60, the ground is extended.As the battery cover 40, the upper body 70, and the ground of the PCB 60are connected, the ground is extended. It is preferable that the secondauxiliary protrusion parts 43 and 46 and the upper body 70 are composedof a metal material.

Radiation performance of the antenna device 100 according to anembodiment of the present invention is described using a Smith chart anda frequency spectrum graph.

FIG. 4A is a diagram illustrating radiation performance of the antennadevice 100 of

FIG. 3A when the battery cover 40 composed of a metal material is notfastened to the lower body 50. FIG. 4B is a diagram illustratingradiation performance of a conventional antenna device in which abattery cover composed of a metal material is fastened to a lower bodybut is not connected to a ground part. FIG. 4C is a diagram illustratingradiation performance of the antenna device 100 of FIG. 3A when thebattery cover 40 of the metal material is fastened to the lower body 50in contact with the ground part 30.

For a better understanding, a Voltage Standing Wave Ratio (VSWR) and aquality factor Q are described.

The VSWR is an index representing a reflection degree of energy input toor output from a circuit or a system, and is a ratio between a minimumvalue and a maximum value of a voltage standing wave at an inputterminal or an output terminal. The VSWR is represented by Equation (1).The voltage standing wave is a stationary wave generated when anadvancing wave is added to a reflected wave returning after reflectionat the input or output terminal.

VSWR=(1+reflection coefficient)/(1−reflection coefficient)   Equation(1)

In Equation (1), when no reflection exists at an input terminal or anoutput terminal, the best value of VSWR equals 1, and when a reflectiondegree is very great, the VSWR approaches infinity. That is, Equation 1represents that, as the VSWR of an antenna approaches 1, the antennaexhibits good radiation performance.

The quality factor Q is an index representing an energy concentrationdegree of a waveform in a frequency spectrum and is represented byEquation (2).

Q=central frequency/3 dB bandwidth   Equation (2)

3 dB bandwidth is a frequency bandwidth between two frequencies 3 dBless than the frequency having maximum energy, i.e. two frequencies eachhaving half of the maximum energy.

In Equation (2), a high quality factor Q represents that energy isconcentrated with a resonance frequency. Frequency selectivity forfiltering only a desired frequency is good from a frequency filterviewpoint.

The antenna device 100 having the radiation unit 10 designed to have aresonance frequency at 1.575 GHz is exemplified.

Referring to FIG. 4A, when the battery cover 40 is not fastened to thelower body 50, the antenna device 100 operates as a monopole antenna andhas a resonance frequency of 1.575 GHz and a VSWR of about 1.26.Referring to FIG. 4B, when the battery cover 40 of a conventionalterminal is fastened to the lower body 50 and does not contact with theantenna device 100 thereof, the antenna device generates two resonancefrequencies each of at about 1.575 GHz, and a VSWR of about 7.30. Thatis, the battery cover composed of a metal material adversely affectsradiation performance of the antenna device of the conventional mobileterminal.

Referring to FIG. 4C, when a type of the antenna device 100 is changedto a PIFA by contacting the battery cover 40 with the antenna device100, the antenna device 100 has a resonance frequency of 1.575 GHz and aVSWR of about 1.75. By contacting the battery cover 40 with the antennadevice 100, the VSWR increases a little compared to that of the case ofFIG. 4A in which the battery cover 40 is not fastened to the mobileterminal, but has no great difference. Referring to FIGS. 4A and 4C,when the antenna device 100 operates as a PIFA, the antenna device 100has a higher quality factor (hereinafter, Q value). The PIFA in whichthe battery cover 40 is connected to the ground part 30 has betterfrequency selectivity. That is, the PIFA can effectively shield anundesired signal. Accordingly, if an antenna device having broadbandcharacteristics is not requested, the antenna device 100 according tothe present invention can be advantageously used.

Through the foregoing description, although the battery cover 40composed of a metal material is used, radiation performance of themobile terminal is not deteriorated by using the antenna device 100according to the present embodiment. When the antenna device 100,according to the present invention, is applied to a mobile terminalusing the battery cover 40 composed of a metal material, radiationperformance can be secured, and thus the mobile terminal can be composedof a metal material. The antenna device 100 can be used as an antennadevice for mobile communication, GPS, Bluetooth, RFID, and digitalbroadcasting reception.

The radiation unit 10 of the antenna device 100, according to thepresent embodiment, is formed as a monopole type antenna, however theradiation unit 10 is not limited thereto. That is, the radiation unit 10can be formed as a PIFA. In this case, the battery cover 40 composed ofa metal material extends the ground of the PIFA. As the battery cover 40is connected to the upper body 70 and the upper body 70 is connected tothe ground of the PCB 60, the ground is extended, however the presentinvention is not limited thereto. For example, a projection may beformed at an upper end of the battery cover 40 and a part of the groundof the PCB 60 may be exposed, so that when the battery cover 40 isfastened to the lower body 50, the battery cover 40 and the ground ofthe PCB 60 directly contact, thereby extending the ground.Alternatively, the PCB 60 may extend to a portion of the lower end ofthe battery cover 40 at which the second auxiliary protrusion parts 43and 46 are positioned, and thus the second auxiliary protrusion parts 43and 46 and the ground of the PCB 60 directly contact, thereby extendingthe ground.

As described above, the antenna device of the mobile terminal, accordingto the present invention, can secure radiation performance in a mobileterminal using a battery cover composed of a metal material. Further, adesign limitation of the mobile terminal due to deterioration ofradiation performance when using a mobile terminal housing composed of ametal material can be solved.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention asdefined in the appended claims.

1. An antenna device of a mobile terminal having a battery covercomposed of a metal material, comprising: a radiation unit fortransmitting and receiving a signal; a feeding unit formed at an endportion of a first side of the radiation unit for electricallyconnecting the radiation unit to a Printed Circuit Board (PCB); and aground part disposed a predetermined distance from the feeding unit andformed at a second side of the radiation unit, wherein when the batterycover is fastened to the mobile terminal, the ground part contacts afirst side of the battery cover.
 2. The antenna device of claim 1,further comprising a carrier for mounting the antenna device.
 3. Theantenna device of claim 1, further comprising a connection member forelectrically connecting the feeding unit and the PCB.
 4. The antennadevice of claim 3, wherein the connection member comprises a C-clip. 5.The antenna device of claim 4, wherein the C-clip is integrally formedwith the feeding unit.
 6. The antenna device of claim 1, wherein aprotrusion part is formed at the first side of the battery cover forcontacting the ground part.
 7. The antenna device of claim 6, whereinthe ground part comprises a first projection extending from an endportion of the ground part, and the protrusion part comprises a secondprojection extending from an end portion of the protrusion part forfastening to the first projection.
 8. The antenna device of claim 1,wherein the battery cover is made from Steel Use Stainless (SUS).
 9. Theantenna device of claim 1, wherein the antenna device operates as amonopole antenna in which the feeding unit and the PCB are connected,when the battery cover is not fastened to the mobile terminal.
 10. Theantenna device of claim 1, wherein the antenna device operates as aPlanar Inverted-F Antenna (PIFA) in which the feeding unit and the PCBare electrically connected and in which the battery cover and the groundpart are connected, when the battery cover is fasten to the mobileterminal.
 11. The antenna device of claim 1, further comprising an upperbody composed of a metal material that contacts the battery cover at asecond side of the battery cover.
 12. The antenna device of claim 11,wherein the upper body contacts the ground of the PCB at a side of thePCB.
 13. The antenna device of claim 1, wherein the battery covercomprises a projection contacting the ground of the PCB.